Genetic variants linked to memory performance found

Boston : Scientists have discovered two common genetic variants that are associated with memory performance. An international research team including scientists from Boston University School of Medicine (BUSM) found genetic variants near the Apolipoprotein E gene, known to harbour an increased risk of dementia (especially Alzheimer's disease), were associated with poorer memory performance, mostly so in the oldest participants.

In a sub-study with post-mortem brain samples, participants with an increasing load of memory risk variants also had more pathological features of Alzheimer's disease, perhaps reflecting in some instances early pre-clinical stages of the disease, researchers said.

According to the study, two additional regions of the genome, pointing to genes involved in immune response, were associated with the ability to recall word lists, providing new support for an important role of immune system dysfunction in age-related memory decline. "Interestingly genetic variants associated with memory performance also predicted altered levels of expression of certain genes in the hippocampus, a key region of the brain for the consolidation of information," said lead author Stephanie Debette, adjunct associate professor of neurology at BUSM.

"These were mainly genes involved in the metabolism of ubiquitin that plays a pivotal role in protein degradation," Debette said. The Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium was developed to facilitate the study of the entire genome through pooling of data from research centres all across the world.

Nearly 30,000 participants who did not have dementia were included in the study. Each participant completed memory tests, such as word recall, and their entire genome was genotyped. Using sophisticated statistical analysis, the genome was examined for segments that were associated with low memory scores.